Shelf unit



FIG. 1 is a front elevational view of a shelf unit showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a cross sectional view taken along line 4--4 of FIG. 1;

FIG. 5 is a rear elevational view thereof; and

FIG. 6 is a perspective view thereof. 

The ornamental design for a shelf unit, as shown and described. 